Biological Bases of Behavior: Heredity, Nervous System, and Senses

Evolutionary Perspective

This approach looks at how behaviors and mental processes have evolved over time to help humans and animals survive and reproduce.

Natural Selection

A process in which organisms with traits that are better suited to their environment tend to survive and reproduce, passing those traits to future generations.

Eugenics

A belief and practice aimed at improving the genetic quality of the human population through selective breeding or other interventions.

Twin Studies

Research that compares identical (monozygotic) and fraternal (dizygotic) twins to understand the influence of genetics and environment on behavior.

Central Nervous System (CNS)

The part of the nervous system that includes the brain and spinal cord.

Peripheral Nervous System (PNS)

The part of the nervous system outside the brain and spinal cord, including all the nerves.

Autonomic Nervous System (ANS)

A part of the PNS that controls involuntary actions like heart rate, digestion, and breathing.

Somatic Nervous System (SNS)

A part of the PNS that controls voluntary movements and sensory information.

Sympathetic Nervous System

A division of the ANS that prepares the body for stressful or emergency situations ("fight or flight").

Parasympathetic Nervous System

A division of the ANS that calms the body down after stress, helping to conserve energy.

Neuron

A nerve cell that transmits electrical and chemical signals in the body.

Glial Cells

Support cells in the nervous system that help nourish, protect, and maintain neurons.

Reflex Arc

A quick, automatic pathway that bypasses the brain to produce a fast response (e.g., pulling your hand away from something hot).

Sensory Neurons

Neurons that carry sensory information from sensory receptors to the brain and spinal cord.

Motor Neurons

Neurons that carry messages from the brain and spinal cord to muscles and glands to produce movement.

Interneurons

Neurons that connect sensory and motor neurons within the brain and spinal cord.

All-or-Nothing Principle

The idea that a neuron either fires completely or not at all, depending on whether it reaches a certain threshold.

Depolarization

The change in a neuron's electrical charge that makes it more likely to fire a signal.

Refractory Period

The period after a neuron fires when it cannot fire again.

Resting Potential

The electrical charge of a neuron when it is not actively sending a signal (negative charge inside).

Reuptake

The process by which neurotransmitters are reabsorbed by the neuron after they have transmitted a signal.

Threshold

The minimum level of stimulation needed to trigger a neural impulse (action potential).

Multiple Sclerosis

A disease that damages the myelin sheath around neurons, slowing down or stopping nerve signals.

Myasthenia Gravis

An autoimmune disorder where the body's immune system attacks the connection between neurons and muscles, leading to muscle weakness.

Excitatory Neurotransmitter

Neurotransmitters that increase the likelihood that a neuron will fire a signal.

Inhibitory Neurotransmitter

Neurotransmitters that decrease the likelihood that a neuron will fire a signal.

Dopamine

A neurotransmitter involved in pleasure, reward, and movement.

Serotonin

A neurotransmitter that affects mood, sleep, appetite, and memory.

Norepinephrine

A neurotransmitter involved in arousal, alertness, and the fight-or-flight response.

Glutamate

The main excitatory neurotransmitter in the brain, involved in memory and learning.

GABA (Gamma-Aminobutyric Acid)

The main inhibitory neurotransmitter in the brain, which reduces neural activity.

Substance P

A neurotransmitter that is involved in the transmission of pain signals.

Endorphins

Neurotransmitters that reduce pain and increase feelings of pleasure.

Acetylcholine

A neurotransmitter that plays a key role in learning, memory, and muscle movement.

Hormones

Chemical messengers produced by glands that regulate body functions like mood, growth, and metabolism.

Adrenaline

A hormone released by the adrenal glands during stress or danger that prepares the body for fight or flight.

Leptin

A hormone that helps regulate energy balance by controlling hunger and fat storage.

Ghrelin

A hormone that stimulates hunger and helps control appetite.

Melatonin

A hormone that regulates sleep-wake cycles, making you feel sleepy at night.

Oxytocin

A hormone that plays a key role in social bonding, childbirth, and lactation.

Agonist Drugs

Drugs that mimic or enhance the effect of a neurotransmitter.

Antagonist Drugs

Drugs that block or reduce the effects of a neurotransmitter.

Reuptake (Again)

The process where neurotransmitters are reabsorbed by the neuron after they've sent their message.

Stimulants

Drugs that increase brain activity, making you feel more alert, awake, or energetic.

Caffeine

A stimulant found in coffee, tea, and some sodas that makes you feel more awake and alert.

Cocaine

A powerful stimulant drug that increases energy and euphoria but can be highly addictive.

Depressants

Drugs that reduce brain activity, leading to relaxation and drowsiness.

Alcohol

A depressant drug that affects the central nervous system, slowing down brain activity.

Hallucinogens

Drugs that alter perception, mood, and consciousness, sometimes causing hallucinations.

Marijuana

A drug from the cannabis plant that can cause altered perception, relaxation, and sometimes hallucinations.

Opioids

A class of drugs that includes pain relievers like morphine, codeine, and heroin.

Heroin

A highly addictive opioid drug that produces intense feelings of euphoria.

Addiction

A condition where a person becomes physically or psychologically dependent on a substance or behavior.

Withdrawal

The physical and psychological symptoms that occur when someone stops using a drug they are addicted to.

Tolerance

The process where the body becomes less responsive to a drug over time, requiring more of the drug to achieve the same effect.

Brain Stem

The part of the brain that connects the brain to the spinal cord and controls basic life functions.

Medulla

A part of the brainstem responsible for controlling vital life functions such as heart rate, breathing, and blood pressure.

Reticular Activating System (RAS)

A network of neurons in the brainstem that regulates wakefulness, alertness, and attention.

Brain's Reward Center

Areas in the brain (like the nucleus accumbens) involved in the experience of pleasure, motivation, and reward.

Cerebellum

The part of the brain that controls balance, coordination, and fine motor skills.

Cerebral Cortex

The outer layer of the brain, involved in high-level functions like thinking, memory, and decision-making.

Hemispheres (2)

The brain is divided into two halves (left and right), each controlling different functions.

Limbic System

A set of structures in the brain involved in emotions, motivation, and memory.

Thalamus

The brain's relay station, directing sensory information (except smell) to the appropriate areas of the brain.

Hypothalamus

A small structure in the brain that controls hunger, thirst, body temperature, and the release of hormones.

Pituitary Gland

A gland located near the hypothalamus that secretes hormones to control other glands in the body.

Hippocampus

A part of the limbic system involved in forming and storing memories.

Amygdala

A part of the brain involved in processing emotions, especially fear and aggression.

Corpus Callosum

A thick band of nerve fibers that connects the two hemispheres of the brain.

Lobes

The four main sections of the cerebral cortex, each responsible for different functions: Occipital: Vision, Temporal: Hearing, memory, and language, Parietal: Sensory processing and spatial awareness, Frontal: Higher functions like decision-making, problem-solving, and movement.

Somatosensory Cortex

A region in the parietal lobe that processes sensory information from the body.

Motor Cortex

A region in the frontal lobe responsible for controlling voluntary muscle movements.

Split Brain Research

Research on individuals who have had their corpus callosum severed, often as a treatment for epilepsy.

Broca's Area

A region in the frontal lobe responsible for speech production.

Wernicke's Area

A region in the temporal lobe involved in language comprehension.

Split Brain Patient

A person whose corpus callosum has been severed to treat severe epilepsy, causing the two hemispheres of the brain to operate independently.

Aphasia

A language disorder caused by damage to the brain, often affecting speech, understanding, reading, or writing.

Brain Plasticity

The brain's ability to reorganize and form new connections in response to learning, experience, or injury.

Brain Scans (EEG, fMRI)

EEG (Electroencephalogram): A test that measures electrical activity in the brain. fMRI (Functional Magnetic Resonance Imaging): A scan that measures brain activity by detecting blood flow.

Lesioning (Brain Surgical Procedure)

A procedure that involves damaging specific areas of the brain to study their function.

Consciousness

The state of being aware of and able to think about one's surroundings, thoughts, and feelings.

Circadian Rhythm (Sleep/Wake Cycle)

The 24-hour biological cycle that regulates sleep and wakefulness in response to environmental cues like light and darkness.

Types of Consciousness (Sleep/Wake)

Different states of awareness, including being awake or asleep.

Disruptions to Circadian Rhythm (Jet Lag)

When the body's internal clock is out of sync with the local time, often due to traveling across time zones.

Sleep Stages (with EEG Patterns)

The different phases of sleep that occur throughout the night, measured by EEG patterns.

NREM Stages 1-3

The stages of non-rapid eye movement (NREM) sleep, ranging from light sleep (Stage 1) to deep sleep (Stage 3).

Stage 1

Light sleep, you can easily wake up.

Stage 2

Deeper sleep, heart rate slows.

Stage 3

Deep sleep, the body does the most physical restoration.

Hypnagogic Sensations

The vivid, often bizarre sensations (like feeling like you're falling) that occur when you're transitioning from wakefulness to sleep.

REM Sleep (Paradoxical Sleep)

A stage of sleep characterized by rapid eye movement, increased brain activity, and vivid dreaming.

Dreaming

The experience of images, ideas, emotions, and sensations during sleep, especially during REM sleep.

REM Rebound

The tendency for the body to increase the amount of REM sleep after a period of sleep deprivation.

Activation-Synthesis Dream Theory

The theory that dreams are the brain's way of making sense of random neural activity during sleep.

Consolidation Dream Theory

The theory that dreams help consolidate memories and information from the day.

Sleep Function (Consolidation/Restoration)

Sleep serves to restore the body and brain and to consolidate memories and learning.

Sleep Disruption Effects

The negative effects on physical and mental health caused by interrupted or insufficient sleep.

Sleep Disorders

Conditions that affect the ability to sleep well, including insomnia, narcolepsy, and sleep apnea.

Insomnia

A sleep disorder characterized by difficulty falling asleep or staying asleep.

Narcolepsy

A sleep disorder where a person suddenly falls asleep during the day, often at inappropriate times.